Copper Speciation for Natural Water by On-site Sample Treatment/Solid-phase Extraction/Inductively Coupled Plasma Mass Spectrometry.

Herein, we determined the contents of Cu(I), Cu(II), and hydrophobic Cu in natural water using on-site sample treatment, solid-phase extraction (SPE), and inductively coupled plasma mass spectrometry (ICP-MS) analysis. To prevent Cu species changes in the sampling, filtering and preconditioning steps were performed in a closed system using plastic syringes and a disposable membrane filter. Bathocuproin disulfonate (BCS) and ethylenediaminetetraacetic acid (EDTA) were selected as a Cu(I)-selective complexing agent and a Cu(II) masking agent, respectively, whereas ascorbic acid (AA) was used to reduce Cu(II) to Cu(I).

Determination of the Acid-Base Dissociation Constant of Acid-Degradable Hexamethylenetetramine by Capillary Zone Electrophoresis.

The acid-base equilibrium of hexamethylenetetramine (hexamine) was analyzed with its effective electrophoretic mobility by capillary zone electrophoresis. Although hexamine is degradable in a weakly acidic aqueous solution, and the degraded products of ammonia and formaldehyde can be formed, the effective electrophoretic mobility of hexamine was measured in the pH range between 2.8 and 6.

Determination of Acid Dissociation Constant of Pravastatin under Degraded Conditions by Capillary Zone Electrophoresis.

The acid dissociation constant of pravastatin was determined under degraded conditions. Pravastatin was degraded in an acidic solution (pH = 2.0) for 5 h, and the degradation solution was subjected to the measurement of the effective electrophoretic mobility by capillary zone electrophoresis.

Determination of trace elements in Ethiopian, Vietnamese, and Japanese women using high-resolution IC-PMS.

Objectives: Humans and other living organisms require small quantities of trace elements throughout life. Both insufficient and excessive intakes of trace elements can have negative consequences. However, there is little information on serum level of trace elements in different populations.

Analysis of ion-association equilibrium of precipitable dipicrylaminate ion in aqueous solution by capillary zone electrophoresis.

The ion-association equilibrium of the dipicrylaminate ion (DPA(-)) was investigated in an aqueous solution with alkali metal ions and with its 18-crown-6 ether complexes as pairing cations by capillary zone electrophoresis (CZE). Although DPA(-) is precipitable with the pairing cations of K(+) and Cs(+) in a homogenous aqueous solution, a low concentration of DPA(-) below its solubility suppressed the formation of the precipitates, and DPA(-) was detected as a usual CZE signal. Changes in the electrophoretic mobility of DPA(-) was analyzed for its ion-association equilibrium.

Micellar electrokinetic chromatography of graphene and chemically modified graphenes with dodecylbenzenesulfonate.

Graphene and chemically modified graphenes were resolved by micellar electrokinetic chromatography (MEKC) using sodium dodecylbenzenesulfonate (SDBS) as a micelle matrix. Graphene was successfully dispersed in a micellar solution, and a consecutive and broad signal was obtained by the MEKC with a 20 mmol dm⁻³ aqueous SDBS solution for Graphene Nanoplatelets. Chemically oxidized graphene was less retained to the micelle than the Graphene Nanoplatelets by the proposed MEKC, and they were resolved with each other.

Fabrication and characterization of a thermostable quinoprotein aldose sugar dehydrogenase immobilized electrode.

We fabricated a thermostable quinoprotein aldose sugar dehydrogenase (tPQQ-ASD derived from a hyperthermophilic archaeon Pyrobaculum aerophilum) immobilized electrode. The electrode was prepared by immobilizing agarose gel mixed with the enzyme and carbon nanofiber (CNF) on a carbon paste (CP) electrode containing p-benzoquinone (BQ) as an electron mediator. The electrocatalytic response was clearly observed by the addition of D-glucose at the electrode.

Micronutrient levels and nutritional status of school children living in Northwest Ethiopia.

Background: Several micronutrients are essential for adequate growth of children. However, little information is available on multiple micronutrient status of school children in Ethiopia. The present study was designed to evaluate the relationship between multiple micronutrient levels and nutritional status among school children.

Multielemental elution behavior of metal ions adsorbed on iminodiacetic acid chelating resin by using hydrogen peroxide as an eluent.

In the present work, we investigated the multielemental elution behavior of metal ions absorbed on iminodiacetic acid (IDA) chelating resin by using hydrogen peroxide (H(2)O(2)) as an eluent. As a result, V(V), Mo(VI), W(VI), Nb(V) and Ta(V) were efficiently eluted by H(2)O(2). In contrast, other metal ions were rarely recovered.

[Study of the removal of Pb2+ from aqueous solution by poly-gamma-glutamic acid coated magnetic nanoparticles].

In this study, a novel low cost magnetic adsorbent material prepared by poly-gamma-glutamic acid (gamma-PGA) coating Fe3o4 magnetic particles, which was called coated magnetic namoparticles (PG-M) was developed for the removal of Pb2+ from water by Dr. Yasuzawa. The particle size of PG-M was about 120-320 nm, and there was no significant difference in Fe3O4 and PG-M particle size, Fe3O4 was only as the support of PG-M core and did not directly involve in the reaction.

Highly selective needle-type glucose sensors prepared by the immobilization of glucose oxidase on γ-polyglutamic acid film.

Fine needle-type glucose sensors with an outer diameter of less that 0.2 mm were fabricated using a low-cost biodegradable γ-polyglutamic acid (PGA) not only as a glucose oxidase (GOx) immobilizing material, but also as a permselective inner membrane. PGA film was prepared on a cellulose acetate-coated Pt-Ir wire electrode, and GOx was covalently immobilized on its surface using water-soluble carbodiimide.

Catalytic properties and crystal structure of quinoprotein aldose sugar dehydrogenase from hyperthermophilic archaeon Pyrobaculum aerophilum.

We identified a gene encoding a soluble quinoprotein glucose dehydrogenase homologue in the hyperthermophilic archaeon Pyrobaculum aerophilum. The gene was overexpressed in Escherichia coli, after which its product was purified and characterized. The enzyme was extremely thermostable, and the activity of the pyrroloquinoline quinone (PQQ)-bound holoenzyme was not lost after incubation at 100 degrees C for 10 min.

Development of a compact system for the determination of lead using a liquid core waveguide and a blue diode as a light source.

A simple and compact system was developed for the on-site analysis of lead in environmental water samples. The system consisted of a custom-made blue diode as a light source, a liquid core waveguide (LCW) as spectrophotometric cell and a compact UV-visible spectrometer. It weighed within 1.

Multielemental characterization of airborne particulate matter collected in Bucharest and Tokushima by inductively coupled plasma mass spectrometry and inductively coupled plasma atomic emission spectrometry.

Airborne particulate matter (PM) collected in Bucharest (Romania) and Tokushima (Japan) was comprehensively characterized through multielemental analysis by ICP-MS to the PM samples. Prior to an elemental characterization of the sample, a multielemental determination method composed of acid digestion (HClO(4)/HNO(3)/HF or H(2)O(2)/HNO(3)/HF) and inductively coupled plasma mass spectrometry/inductively coupled plasma atomic emission spectrometry (ICP-MS/ICP-AES) was established to analyze a certified reference material of vehicle exhaust matter (NIES No. 8) for verifying the method.

An amperometric D-amino acid biosensor prepared with a thermostable D-proline dehydrogenase and a carbon nanotube-ionic liquid gel.

Carbon nanotube (CNT) gel, which is composed of a mixture of single-wall CNT, an ionic liquid, and a thermostable D-proline dehydrogenase (D-Pro DH) immobilized electrode was utilized for the determination of D-amino acids (DAAs) in food samples. When a critical comparison with CNT, Ketjen Black (KB), and carbon powder (CP) was also carried out, the CNT/D-Pro DH immobilized electrode showed the highest sensitivity and the lowest detection limit of D-proline. In addition, the CNT/D-Pro DH immobilized electrode was applied to detection of DAAs in rice wine and vinegar samples.

Relationship of low serum selenium to anemia among primary school children living in rural Vietnam.

A cross-sectional study of 292 primary school children was conducted in rural Vietnam to investigate the relationship among micronutrient deficiencies, and other risk factors for anemia. Serum levels of iron, copper, zinc, selenium and magnesium were determined by inductively coupled plasma mass spectrometry and that of retinol by high performance liquid chromatography. Hemoglobin concentration in whole blood was measured by the cyanmethemoglobin method.

Association of low serum selenium with anemia among adolescent girls living in rural Vietnam.

Objective: We investigated the prevalence of anemia and deficiency in trace elements in adolescent girls living in rural Vietnam.

Methods: Two hundred forty-five adolescent girls 11-17 y of age from three schools in rural province of Ha Nam, Vietnam, were assessed.

Results: The prevalence of anemia was 20.

Development of a D-amino acids electrochemical sensor based on immobilization of thermostable D-proline dehydrogenase within agar gel membrane.

A novel biosensor for determination of d-amino acids (DAAs) in biological samples by using an electrode based on immobilization of a thermostable d-Proline dehydrogenase (d-Pro DH) within an agar gel membrane was developed. The electrode was simply prepared by spin-coating the agar solution with the d-Pro DH on a glassy carbon (GC) electrode. An electrocatalytic oxidation current of 2,6-dichloroindophenol (DCIP) was observed at -100mV vs.

Simultaneous determination of trimethyl-and triethyllead in urban dust by species-specific isotope dilution/gas chromatography-inductively coupled plasma mass spectrometry.

Both (206)Pb-labeled trimethyllead (TML) and triethyllead (TEL) were synthesized from (206)Pb-enriched metallic Pb certified reference material (NIST SRM 983) and iodomethane or iodoethane through a one-process reaction in a closed system using centrifuge tubes, respectively. Organolead compounds in an urban dust reference material (BCR CRM 605) were extracted with an acetic acid/methanol (1:1) solution, which was mechanically shaken for 24 h. After adjusting the pH of the extracted solution to pH 5, the extracted organolead compounds were derivatized by tetrabutylammonium tetrabutylborate (TATB) and measured with GC-ICPMS.

Micronutrient deficiencies and anemia among preschool children in rural Vietnam.

The prevalence of trace elements deficiencies, vitamin A deficiency, anemia, and their relationships were investigated in a cross sectional study involving 243 children aged from 12 to 72 months in rural Vietnam. Serum levels of copper, zinc, selenium and magnesium were determined by inductively coupled plasma mass spectrometer and that of retinol by high performance liquid chromatography. Hemoglobin concentration in whole blood was measured by the cyanmethemoglobin method.

Serum zinc, copper, selenium, calcium, and magnesium levels in pregnant and non-pregnant women in Gondar, Northwest Ethiopia.

Pregnant women in developing countries are vulnerable to multiple micronutrient deficiencies. Studies assessing serum levels of the micronutrients and magnitude of their deficiencies are very scarce in African subjects. This study was aimed at determining serum levels of micronutrients in 375 pregnant (42 HIV seropositive) and 76 non-pregnant women (20 HIV seropositive) who visited the University of Gondar Hospital, Gondar, Ethiopia.

Characterization of a glucose sensor prepared by electropolymerization of pyrroles containing a tris-bipyridine osmium complex.

A glucose sensor was developed by electrocopolymerization using pyrroles containing a tris-bipyridine (bpy) osmium complex (Os-py), pyrrole (py), pyrrole propanoic acid (PPA) and glucose oxidase (GOx) to improve the key performance characteristics, such as the sensitivity, selectivity, and long-term stability. Tris-bipyridine osmium pyrrole complexes with four different methylene moieties were utilized to correlate the methylene length with the glucose sensor performance. The electrocatalytic response of glucose was clearly observed at electrodes modified with Os-py, except for the electrode immobilized with the Os-py complex containing the shortest methylene moiety.

Serum levels of trace elements and iron-deficiency anemia in adult Vietnamese.

This study was aimed at assessing the serum levels of vitamin A, copper, zinc, selenium, and iron among adult Vietnamese with and without iron-deficiency anemia. Blood was collected from adult Vietnamese living in the midland of northern Vietnam. One hundred twenty-three subjects in the age range 20-60 yr were included in the study.

A multielement masking method using magnesium hydroxide coprecipitation for the selective determination of lead in water samples by differential pulse anodic stripping voltammetry.

We present a new multielement masking method using magnesium hydroxide coprecipitation for the selective determination of Pb by differential pulse anodic stripping voltammetry (DPASV). The recovery of Pb in the masking method was over 95%, while interfering ions (Cd(2+), Co(2+), Cu(2+), Fe(3+), Mn(2+), and Ni(2+)) could be removed at 100% from the analytical sample. A linear regression was obtained in the Pb concentration from 10 to 1000 microg kg(-1) in the existence of 100 microg kg(-1) of the interfering ions.